Electrical follow-up movement



March 30, 1943. E. zAcHARlA 2,315,176

ELECTRICAL FOLLOW-UP MOVEMENT Filed'May 9, 1938 4 Sheets-Sheet 1 IZz'gJ l March 30, 1943. E ZACHARM ELECTRICAL FOLLOW-UP MOVEMENT Filed May 9, 1958 4 Sheets-Sheet 2 I In en/0;": if? 2444;

March 30, 1943. E. zAcHARl'A ELECTRICAL FOLLOW-UP MOVEMENT 4 Sheets-Shed 5 Filed May 9, 1958 March 30, 1943. E ZACHARIA 2,315,176-

ELECTRIGAL FOLLOW-UP MOVEMENT 4 Sheets-Sheet 4 Filed May 9, 1938 fnvenfor":

Patented Mar. 30, 1943 ELECTRICAL FOLLOW'-UP MOVEMENT Erich Zacharlit, Berlin-Zehlendori', Germany; vested in the Alien Property Custodian Application May 9, 1938, Serial No. 206,931 In Germany May 10, 193'1 6 Claims.

The invention refers to electrical follow-up devices particularly designed for the transmission of movements. The principal object of the present invention is to provide a novel apparatus of the above character which has no mechanical contacts. If it concerns a transmitting system in which the transmitter is influenced by only very small directional forces, as it is the case in trans mitting compass indications, many difllcultles occur when using mechanical contacts on the transmitter side to close or interrupt in dependance on the position of the transmitter a circuit which effects the follow-up movement. Due to these small directional forces all apparatus should be avoided having transmitters with builtin mechanical sliding contacts which produce inaccuracies and uncertainty.

According to the present invention, the follow-up device is provided with means for producing a glow discharge between electrodes, said glow discharge acting as contact and being set into or out of operation in dependance on the movement to be transmitted, thereby closing and interrupting, respectively, an electrical circuit for operating means effecting the follow-up movement. The glow-discharge is of characteristic feature of the ion-tubes, difiering from the electron-tubes in that not the intensity of the discharge is variable but the beginning of the discharge. The ion-tubes operate like a contact, as either no current flows through the tube or it flows through the tube with its entire intensity,

whereby the beginning of the discharge depends on the voltage drop between the electrodes of the ion-tube, on type of gas and on the gas pressure, on the form and material of the electrodes and the length of the discharge path. The object of the invention is based on the principle to vary the beginning of the discharge by changing the length of the discharge path.

In order that the present invention may be well understood some embodiments thereof will now be described by way of example with reference to the accompanying drawings, in which Fig. 1 shows in elevation a follow-up device, such as a compass, according to the invention with parts in vertical section.

Fig. 2 is a plane view of Fig. 1 taken on line 2--2 of Fig. 1.

Fig. 3 shows the complete wiring of the apparatus shown in Figs. 1 and 2.

Fig. 4 is a mod'iication of the part as in Fig. 2.

Figs; 5 and 6 are wiring diagrams,

Referring now to Fig. 1: In a housing i6, preferably of glass, containing a rare gas of small pressure there are provided bearings 3, 4 on which an axle 22' is mounted for rotation carrying in a well-known manner a series of magnets l. 5 is a metal body having an annular groove relative to which the ends of the compass-magnets i move during variations in the course of a vessel upon which the compass is mounted, thereby producing-eddy currents in the metal body 5 and damping the movement of the magnets i with respect to the housing IS. A funnel-like member 6 carries on the one hand the lower bearing 3 and on the other hand the metal ring 5 and has a projection l2 directed downwards which is embedded in the foot of the housing l6. An angle-formed part I connected to the metal ring 5 carries the upper bearing 4.

The axis 2--2 has an insulating intermediate piece 8 to which is connected a two-armed conducting member 9, the ends of which are directed downwards. These ends cooperate with two electrodes I0, I i, each being cylindrically shaped and being concentrically and symmetrically arranged with respect to the axis 2-2' (Fig. 2), thereby forming two discharge paths. The two electrodes are carried by the conducting wires or rods I3, I 4, the lower ends of which are melted into the foot of the housing IS. The lower part of the housing I6 is carried by a socket IT with two plugs l9, one of said plugs being connected directly to the conducting wire 13, whilst a series resistance i8 is in circuit between the conducting wire it and the other of the plugs [9. These plugs are in contact with conducting bushings 20 provided in a second socket 2i and connected to slip-rings 22, 23, respectively, carried by the socket 2 I. Two brushes 24, 25 sliding upon these slip-rings are connected to an alternating current source and are carried by the casing of a motor 21 within said casing, the shaft 26 of which is in rigid connection with the socket 2|.

The complete wiring is shown in Fig. 3. 28 is the alternating current source producing at the electrodes H], H a voltage drop suflicient for producing a glow discharge between each of the electrodes I0, II and the bridging conductor 9. Within this circuit are further the series resistance l8, before mentioned, for limiting the discharge current and the coil 29 of a relay 30. The armature of the relay 30 cooperates with the contacts 3!, 32, thereby connecting either the coil 33 or the coil 34 of a well-known reversible motor 21 to the alternating current supply.

If the conducting member 9 approaches the electrodes l0, ll so that a discharge is produced thereversible motor 38 begins to run in the opposite sense and to turn the housing and the electrodes III, II anticlockwise so as to decrease the distance between the ends of the bridging member II and the electrodes II, II until the discharge again begins. Thereiore, whatever may be the position of the magnetic needles relative to the vessel carrying the compass, the electrodes always follow up the movements of the conductor 9 relative to the vessel.

A capacity 38 is connected parallel with the alternating current source 24. 'As soon as the glow discharge between the electrodes and the bridging member begins, the capacity also discharges itself over the relay coil 29, the resistance I8 and the discharging paths the discharging current of the capacity thereby further exciting the coil 29 of the relay iii.

The described shape of the electrodes has the advantage that even in the case or rapid changes in the direction of the movement of the compass needles, the follow-up movement of the electrodes III, II is guaranteed.

To obtain definite conditions over the whole range of the movement of the transmitter one arm of the conducting bridge may be shortened, whilst accordingly one of the two electrodes e. g. the electrode I I may be arranged at a smaller distance with respect to the turning axis of the magnet needles, as illustrated in Fig. 4. The bridging member 9 has again two ends extending downwards cooperating with, the electrodes and thereby forming discharging paths. Therefore, in the case the larger arm 01' th bridging member is next to the electrode II which condition may occur if the bridging member 8 has swung over 180 with respect to the housing IS, the paths between bridge 9 and electrodes I0, II are too large as to produce a discharge between these parts. Even in the case of rapid rotation of the needles by 180 with respect to a given position, controlling impulses derived from the two considered positions are not equal; therefore 180 ambiguity in the indication of the repeater compass is avoided. Obviously the follow-up device oscillates uninterruptedly near the position of the compass needles. This may be avoided by using two separate glow discharge paths as illustrated in Fig. 5, showing at the same time the complete wiring.

42 and 43 are two electrodes separated by a certain distance, each of said electrodes cooperating alternatively through the medium of the bridging member 9 with the electrode 44, common to both, and forming discharge paths, if the bridging member is moving from a certain position clockwise or anticlockwise. Similar to the arrangement in Fig. 4, the arm of the bridging member 8 cooperating with the electrode 44 is shortened, and corresponding thereto, also the distance of said electrode with respect to the turning axis of the member 9. In the illustrated position the glow discharge is produced between the electrodes 44 and 42. Thereby the relay 45 is excited and switches on the motor 44 by means of the two contacts 46, 41, the motor 48 having a field coil 45 and an armature 50 so as to turn the elecasiarre a trodes to the right until the longer arm 0! the bridging member I runs between the two elecf trodes 42, 48 and, therefore, no discharge is taking place so that the motor is switched all due to the interruption or the contacts 44, 41.

The motor 4| is running in the other direction, when the bridge 9 lies over the electrode 43 thereby producing glow discharges between these parts and exciting the coil of the relay II which switches on the two contacts I2, 53. As a result the current fiows through the armature II in the opposite direction, thus changing the direction 0! rotation of the motor.

In the illustrated embodiment 54 is a direct current source. In order that the glow discharge may be interrupted it the longer arm of the bridging member 9 moves away from the electrode 42 or 43, respectively, 1. e. if the length of the discharge path increases, a periodically operated interrupter 55 is provided.

It is not necessary to use two electrodes between which the bridging member is moved. In

'this case it is possible to use the bearing of the magnet system I as conductor of the current as shown in Fig. 6. In this arrangement the magnetic system I itself is used as the one electrode which cooperates with the other electrode II. As a further modification the entire follow-up device may be enclosed in the housing II. I

In order to avoid changing the magnetic characteristics of the magnet system under the infiuence of the glow discharge, a conducting connection may be avoided between the bridging member and the magnet system which may be effected by the insulated member 8 of Fig. 1.

Whatis claimed is:

1. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing; a first pair 01' electrodes carried by said magnet system; said electrodes being arranged at different distances with respect to the pivot axis of the compass magnet system and electrically connected to one another; a second pair of electrodes fixedly mounted within said casing at difi'erent distances with respect to the pivot axis oi the compass magnet system corresponding to the different distances of the electrodes of said first pair; the electrodes arranged at the corresponding distances cooperating with one another for forming a glow discharge path each; whereby the efi'ective length of said glow discharge paths are varied on change in the position of the casing relative to the earth magnetic field.

2. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing; a first electrode can'ied by said compass magnet system; two second electrodes fixedly mounted within said chamber each being arcuate and concentric with respect to the pivot axis; said first electrode cooperating with one of said second electrodes corresponding to the relative angular displacement or the compass magnet system and said casing forming thereby a glow discharge path each; said second electrodes forming together with the first electrode a neutral discharge zone; whereby the eflective length of said glow discharge paths are varied on change in the position of the compass casing relative to the earth magnetic field.

3. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing; said magnet system carrying an elec-, trode; and a second electrode fixedly connected to said chamber for producing or interrupting a glow discharge between said electrodes in dependence on the position of the compass magnet system in azimuth relative to the compass casing.

4. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing; a first pair of electrodes carried by said magnet system; said electrodes being arranged at the same distance from the pivot axis 0! the compass magnet system and electrically connected to one another; and a second pair of electrodes arranged concentrically of the pivot axis and fixedly mounted within said casing; the electrodes of said first pair cooperating with the electrodes of said second pair respectively for producing or interrupting a glow discharge between .the cooperating electrodes in dependence on the position in azimuth of the compass magnet system relative to the compass casing ii. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing; a first pair of electrodes carried by said diiterent distances from the pivot axis of the compass magnet system and electrically connected to one another: and a second pair of electrodes fixedly mounted within said casing at different distances with respect to the pivot axis of the compass magnet system corresponding to the difl'erent distances of the electrodes of said first pair; the electrodes arranged at the corresponding distances cooperating with one another for producing or interrupting a glow discharge between the cooperating electrodes in dependence on the position in azimuth of the compass magnet system relative to the compass casing.

6. In a magnetic compass the combination of a closed casing containing gas at a pressure smaller than normal sea level atmospheric pressure; a compass magnet system pivoted in said casing: a first electrode carried by said compass magnet system; two second electrodes fixedly mounted within said casing; said first electrode cooperating with one or the other of said second electrodes corresponding to the direction of displacement of the compass magnet system relative to the compass casing for producing or interrupting a glow discharge between the cooperating electrodes in dependence on the position in azimuth of the compass magnet system relative to the compass casing.

ERICH ZACHARIK.

magnet system; said electrodes being arranged at i 

